X-bit labs

ATI RADEON X800: R420 Totally Exposed (page 14)

Category: Video

by Tim Tscheblockov , Alexey Stepin , Anton Shilov

[ 05/04/2004 | 06:42 AM ]

Additional performance growth in case of enabled anisotropic filtering can be obtained only at the expense of further image quality worsening. For instance, NVIDIA graphics processors use a mixture of bi-linear and tri-linear filtering instead of the fully-functional tri-linear filtering, and ATI chips use tri-linear filtering only for the first texture even in Quality mode, when anisotropic filtering is forced.

By the way, the control panel of NVIDIA driver allows disabling all anisotropic filtering optimizations for NVIDIA GeForce 6800 Ultra. In this case, all images obtained on GeForce 6800 Ultra get fully-fledged tri-linear filtering.

The screenshots below were taken on NVIDIA GeForce 6800 Ultra working in such a mode: in the upper left corner you see bi-linear filtering, in the upper right – tri-linear filtering, in the lower left – 4x anisotropic filtering combined with tri-linear filtering, and in the lower right – 16x anisotropic filtering combined with tri-linear filtering.

NVIDIA GeForce 6800 Ultra

We decided to estimate how the texture quality changes depending on the image quality settings in the drivers with the help of the good old Serious Sam game.

The image quality settings in Serious Sam were at the maximum, but the maximum level of anisotropic filtering was forced from the driver control panel: in Serious Sam only tri-linear filtering was enabled.

At first let’s compare the results obtained from ATI RADEON X800 XT Platinum Edition and RADEON 9800 XT. The screenshots should be read as follows: RADEON X800 XT in Quality mode, RADEON X800 XT in Performance mode, RADEON 9800 XT in Quality mode, RADEON 9800 XT in Performance mode:

RADEON X800 XT

Quality mode	Performance mode

RADEON 9800 XT

Quality mode	Performance mode

The differences between the images obtained on RADEON X800 XT and RADEON 9800 XT cannot be noticed with a naked eye. In Performance mode, RADEON X800 XT as well as the RADEON 9800 XT, disables tri-linear filtering, which can be seen not only in dynamics, but also on the static images.